What recession? In Venice, party rolls on

Sighicelli calls it, coyly, "Untitled (The Party's Over)."

With the art world supposedly in crisis - prices dropping, profits of auction houses plummeting, museums engaged in drastic cost-cutting - a provocation like this might hit a nerve. But instead the video has passed largely unnoticed, and the art world has gone on doing what it does best: partying, partying, and more partying.

Recession be damned. Evidence of ludicrous wealth is everywhere at the Biennale, which officially opens today. Cartoonishly sleek yachts, all registered in the Cayman Islands, line the Grand Canal near the entrance to the Biennale. Politicians and art collectors have arrived at the numerous exhibition openings all over the lagoon by water taxi, many of the men with trophy wives in tow.

Naomi Campbell, accompanied by a beefed-up bodyguard, tried to look attentive through a guided tour of the Russian Pavilion. And Francois Pinault, the French billionaire who owns Christie's, opened a new venue, the Punta della Dogana, redesigned by architect Tadao Ando, to show off a collection of art that looked like nothing so much as an auction house catalog come to life.

The weeklong vernissage, or preview, of the Venice Biennale is always like this. Press from all over the world scurry around the city trying to find the best shows. Collectors and artists get friendly. And plenty of people not officially affiliated with the Biennale try to get in on the act.

This year, for instance, posters designed by Shepard Fairey can be seen throughout the city, giving Venice an appearance uncannily reminiscent of Boston. Fairey was invited by SMS Venice, a nonprofit organization that hopes to raise money for the preservation of key buildings here by auctioning Fairey's murals. He told the Globe he had obtained official permission for his posters on the Grand Canal, but not for all those pasted elsewhere in the city.

But the main games in town, as always, are the national pavilions in the Giardini and the sprawling group exhibitions that fill the Palazzo delle Espozioni in the Giardini and the nearby Arsenale with contemporary art from around the world.

The US Pavilion this year is dedicated to a career survey of the work of the 68-year-old sculptor, video artist, and sound artist Bruce Nauman, described in a recent New Yorker profile (and not for the first time) as "the most influential living artist." The exhibition, called "Topological Gardens," was organized by the Philadelphia Museum of Art, and it extends to two other locations. Taken together, the three shows make for one of the most compelling presentations in a strong field.

Several other national pavilions stand out. The Danes teamed up with the Nordic Pavilion (Finland, Norway, and Sweden) to stage a parody of two wealthy art collectors' homes. The contrived tableau is funny and disturbing in equal parts, and it comes replete with a lifelike body floating face down in a swimming pool and, lounging on a chair reading a book, a naked young man who is more than just life-like.

The Russians, with bold and nerve-jangling shows by three artists, and the Brits, with a pensive and lyrical film by the artist Steve McQueen, have also put in strong showings. Meanwhile, over at the Polish Pavilion, MIT-based Krzysztof Wodiczko, who will have a projection-based exhibition at Boston's Institute of Contemporary Art in November, has mounted an evocative show about immigrant workers. It is outstanding.

But perhaps the real story this year is that the official Biennale is being conspicuously upstaged by the so-called "collateral events" - independent exhibitions mounted elsewhere in the city. The best of these is at the Palazzo Fortuny, the majestically disheveled former residence and workshop of the great textile designer, painter, inventor, photographer, and dressmaker Mariano Fortuny. Pretentiously called "In-finitum," it is the third in a trilogy of shows that started in Venice during the 2007 Biennnale.

Conceived by collector and dealer Axel Vervoordt, the exhibition displays work by some of the biggest names in contemporary and 20th-century art alongside old masters, ancient sculptures, Asian art, textiles, and various installations.

When collectors take over the work of curators and try to stage intelligent and intelligible shows, their efforts can easily backfire. Pinault's two displays of his splashy collection, at the Punta della Dogana and the Palazzo Grassi, are a case in point: They smack of an arriviste's susceptibility to bloated works by fashionable names.

But with "In-finitum," Vervoordt, guided largely by intuition, has attempted something no academically trained curator would dream of. In pulling it off, he has created an astonishing exhibition, made all the more so by its unforgettable setting.